Photographic objective with selectable diaphragm stops



A. BAAB ETAL Feb. 1, 1966 PHOTOGRAPHIC OBJECTIVE WITH SELECTABLE DIAPHRAGM STOPS Filed April 26, 1963 United States Patent 3,232,200 PHOTOGRAPHIC OBJECTIVE WITH SELECTABLE DIAPHRAGM STOPS Albert Baab and Paul Himmelsbach, Bad Kreuznach, Germany, assignors to J. Schneider & Co., Optisehe Werke, Bad Kreuznach, Germany, a corporation of Germany iled Apr. 26, 1963, Ser. No. 275,952 Claims priority, applicatiimsGermany, Apr. 27, 1962, 3 3 1 8 Claims. cl. 9564) Our present invention relates to a photographic objective, particularly (but not exclusively) for photocopying equipment, having means for selecting different diaphragm stops of predetermined sizes. In certain instances, e.g. for a preliminary exposure to record a raster or similar background in photocopying work, it is necessary to use a diaphragm aperture of accurately selected diameter not generally realizable with adjustable diaphragms. The conventional iris-type diaphragms, for example, do not lend themsleves to precise setting especially in the region of the smaller diameters, e.g. for relative apertures in the range of 1:64 to 1:260.

It is, therefore, the principal object of our present invention to provide simple means for enabling the selection of predetermined diaphragm stops in a given range of relative apertures, advantageously in combination with an adjustable (e.g. iris-type) diaphragm operative most effectively in a different range.

, A more specific object of this invention is to provide a diaphragm-stop selector of this character which may be conveniently removed from the objective system when not needed or when difierently calibrated fixed stops are required.

The foregoing objects are realized, in accordance with the instant invention, in an objective whose housing is provided with a lateral slot for the insertion of a plateshaped holder which, in its operative position, extends completely across the interior of the housing preferably in the immediate vvicinity'of an iris diaphragm. In the region of the objective axis, which generally .coincides with the axis of the 'iris diaphragm, the holder is formed with an opening spanned bya movable disk having a plu rality of diaphragm a pertures of different diameters, this disk being adjustable from without to align a selected diaphragm aperture with the objective axis. In a preferred embodiment, the opening in the holder is circular and eccentric with reference to the objective and its housing, the center of this opening being advantageously positioned intermediate the housing axis and the lateral slot so that the apertured disk, which is also circular and rotatably received in that opening, can be conveniently operated with the aid of a projecting pinion which meshes with gear teeth on the disk periphery. 'The pinion, which is thus positively coupled with the disk, may be provided with markings viewable through a suitably positioned window in the holder for indicating the selected diaphragm stop.

The invention will be described in greater detail with reference to the accompanying drawing in which:

FIG. 1 is a side-elevational view of a photocopying objective incorporating a diaphragm holder according to the invention;

FIG. 2 is a cross-sectional view taken on the line IIII of FIG. 1, showing the diaphragm holder in face view;

FIG. 3 is a face view of the same holder, similar to that of FIG. 2 but drawn to a larger scale and with parts broken away;

FIG. 4 is a longitudinal sectional view of the holder, taken on the line IV-IV of FIG. 3; and

FIG. 5 is a cross-sectional view of the holder, taken on the line VV of FIG. 3.

In FIGS. 1 and 2 we have shown an objective with a generally cylindrical housing 1 containing the usual shutter and lenses (not shown) as well as a conventional iris diaphragm 2. The housing is formed, immediately behind the diaphragm 2, with a lateral slot 7a and with a pair of segmental shoulders 1b, 1c whose spacing corresponds to the length of the slot and which define a rectangular guideway, within a radial plane of the housing, for a [plate-shaped holder 15 slida-bly inserted through that slot. The holder 15 comprises a flat body 3 with parallel sides and a curved bottom, the latter coming to rest against the inner housing wall so as to prevent the passage of any light rays around the edges of the holder. The top of the holder body 3 projects outwardly through slot 1a and is provided on its sides with milled edges 3a, 3b to facilitate its extraction.

Holder body 3 is further formed with a circular opening 4 whose center is radially offset, in an upward direction as viewed in FIG. 2, from the optical axis 0 of the system which is also the axis of housing 1 and diaphragm 2. This axis traverses a peripheral zone of an opaque disk 5 rotatably lodged in the opening 4, this disk having a plurality of angularly spaced diaphragm apertures 6a, 6b, 6c, 6d, 6e of progressively increasing diameter. It may be assumed, for example, that these apertures represent diaphragm stops in the range of 1:260 to 1:64 Whereas the iris diaphragm 2 controls the larger aperture ratios, e.g. from 1:64 to 1:9. In the particular position of disk 5 illustrated in FIG. 3, the second-smallest aperture 6b (representing the stop 1:180) is aligned with the housing axis 0.

Holder body 3 has a shallow recess 4a, whose outline converges toward the upper portion of the holder projecting from slot 1a, and is provided at that upper .portion with a deeper recess 4b accommodating a pinion 8 which is journaled in the holder by means of a pin 8a. Pinion 8 meshes with gear teeth 7 on the periphery of disk 5 and, furthermore, extends beyond holder 15 through slot 1a so that its projected toothed rim may be readily engaged by the fingers of the user to rotate the disk 5 for the selection of another diaphragm stop. A retaining plate 9, fitting within recess 4a, is secured to holder 3 by screws 16 so as to be readily detachable therefrom when it is desired to replace the disk 5 by another disk having different diaphragm apertures. A hole 10 near the lower end of plate 9 is centered on the axis 0 and has a diameter larger than at least those of the four smaller diaphragm apertures 6a to 6d. It will be understood that the largest aperture 6e could be of the same size as hole 10 or even wider than the latter, the hole 10 defining in that case the largest diaphragm stop of the attachment 5, 15.

Suitable markings indicative of the selected diaphragm apertures may be conveniently provided on the pinion 8. As here shown, these markings 12 are visible through a window 11 near the top of retaining plate 9 which projects from the slot 1a. Furthermore, the disk 5 and the holder 15 may be provided with co-operating indexing means for releasably arresting the disk in any selected operating position; in the embodiment illustrated, we provide for this purpose a ball check in a bore of disk 5, the ball 5a being yieldably urged by a flat spring 5b into one of several depressions 9' on plate 9.

For certain types of exposure it will be desirable to use an optical filter which, accordingly, is advantage ously carried directly on the attachment 5, 15 so as to be insertable therewith into the objective. In the present embodiment the retaining plate 9 is recessed, for this purpose, at 911 to accommodate a transparent filter plate 14, of suitable color, which may be removably held in place by a mounting ring 17 frictionally engaging the plate 9. In this manner the filter 14 may be readily taken oft or replaced upon withdrawal of the attachment from the objective housing.

When the attachment 5, 15 is not in use, i.e. when the exposures are to be controlled by the iris diaphragm 2, a masking ring 13 on housing 1 may be rotated from its illustrated position (FIG. 1) so that a segmental flange 13a thereof, extending axially from the milled periphery of that ring, overlies the slot 1a to shut off any passage of light therethrough.

Our invention is, of course, not limited to the specific details of construction described and illustrated but may be embodied in various modifications of the disclosed system without departing from the spirit and scope of the appended claims.

We claim:

1. In a photographic objective, in combination, a generally cylindrical housing, an iris diaphragm in said housing centered on the axis thereof, said housing being provided with a lateral slot, a plate-shaped holder slidably disposed in said housing adjacent said iris diaphragm and projecting outwardly from said slot for removal from said housing, said holder extending completely across the interior of said housing in a radial plane thereof and being provided with an opening in line with said axis, a disk movable on said holder, said disk spanning said opening and being provided with a plurality of diaphragm apertures of different diameters selectively alignable with said opening for controlling the passage of light rays therethrough, disk-operating means extending outwardly from said housing through said slot for selectively aligning said apertures with said axis, and a rotatable ring on said housing adjacent said slot, said ring being provided with a segmental axially extending flange movable into a position overlying said slot for preventing the entrance of light therethrough into said housing upon removal of said holder.

2. The combination defined in claim -1, further comprising co-operating indexing means on said holder and said disk for releasably maintaining the latter in a selected position.

3. In a photographic objective, in combination, a generally cylindrical housing provided with a lateral slot, a plate-shaped holder slidable disposed in said housing and projecting outwardly from said slot for removal from said'housing, said holder extending completely across the interior of said housing in a radial plane thereof and being provided with a circular opening in line with the axis of said housing, said opening having a center offset from said axis, a circular disk rotatably lodged in said opening, said disk being provided with a plurality of peripherally spaced diaphragm apertures of different diameters selectively alignable with said opening for controlling the passage of [light rays therethrough, and disk-rotating means extending outwardly from said housing through said slot for selectively aligning said apertures with said axis, the center of said opening being disposed between said axis and said slot, said disk being provided with peripheral gear teeth, said disk-rotating means including a pinion on said holder projecting partly therefrom at said slot and meshing with said gear teeth.

4. The combination defined in claim 3 wherein said holder has an exposed portion registering with the projecting part of said pinion, said portion being provided with a window, said pinion bearing markings viewable through said window for indicating the size of a diaphragm aperture on said disk aligned with said axis.

5. The combination defined in claim 3 wherein said holder comprises a flat body and a retaining plate detachably secured to said body, said retaining plate having a hole centered on said axis, said hole being larger than all except at most one of said diaphragm apertures.

6. The combination defined in claim 5 wherein said retaining plate has an exposed portion registering with the projecting part of said pinion, said portion being provided with a window, said pinion bearing markings viewable through said window for indicating the size of a diaphragm aperture on said disk aligned with said hole.

7. The combination defined in claim 5 wherein said retaining plate and said disk are provided with cooperating indexing means tor releasably maintaining said disk in a selected position.

8. The combination defined in claim 3, further comprising an optical filter plate in said opening adjacent said disk.

References Cited by the Examiner UNITED STATES PATENTS 1,512,785 10/ 1924 Mittasch -64 2,015,261 9/1935 Eckler 95-64 2,380,216 7/ 1945 Carter 95-64 FOREIGN PATENTS 909,863 11/ 1962 Great Britain.

NORTON ANSHER, Primary Examiner. CLIFFORD B. PRICE, Assistant Examiner. 

1. IN A PHOTOGRAPHIC OBJECTIVE, IN COMBINATION, A GENERALLY CYLINDRICAL HOUSING, AN IRIS DIAPHRAGM IN SAID HOUSING CENTERED ON THE AXIS THEREOF, SAID HOUSING BEING PROVIDED WITH A LATERAL SLOT, A PLATE-SHAPED HOLDER SLIDABLY DISPOSED IN SAID HOUSING ADJACENT SAID IRIS DIAPHRAGM AND PROJECTING OUTWARDLY FROM SAID SLOT FOR REMOVAL FROM SAID HOUSING, SAID HOLDER EXTENDING COMPLETELY ACROSS THE INTERIOR OF SAID HOUSING IN A RADIAL PLANE THEREOF AND BEING PROVIDED WITH AN OPENING IN LINE WITH SAID AXIS, A DISK MOVABLE ON SAID HOLDER, SAID DISK SPANNING SAID OPENING AND BEING PROVIDED WITH A PLURALITY OF DIAPHRAGM APERTURES OF DIFFERENT DIAMETERS SELECTIVELY ALIGNABLE WITH SAID OPENING FOR CONTROLLING THE PASSAGE OF LIGHT RAYS THERETHOUGH, DISK-OPERATING MEANS EXTENDING OUTWARDLY FROM SAID HOUSING THROUGH SAID SLOT FOR SELECTIVELY ALIGNING SAID APERTURES WITH SAID AXIS, AND A ROTATABLE RING ON SAID HOUSING ADJACENT SAID SLOT, SAID RING BEING PROVIDED WITH A SEGMENTAL AXIALLY EXTENDING FLANGE MOVABLE INTO A POSITION OVERLYING SAID SLOT FOR PREVENTING THE ENTRANCE OF LIGHT THERETHROUGH INTO SAID HOUSING UPON REMOVAL OF SAID HOLDER. 